1. Field of the Invention
The present invention relates to sulfur containing cement compositions. More particularly, the invention relates to a cement composition based upon compounds of sulfur with cyclopentadiene.
2. Description of the Prior Art
The use of sulfur in the preparation of construction materials had been proposed as early as just after World War I when an acid resistant mortar compound of 40% sulfur binder mixed in 60% sand was prepared. However, upon thermal cycling such mortars exhibit a loss in flexural strength resulting in failure of the mortars. The use of sulfur as a binder in the preparation of concretes when combined with an agregate such as crushed rock or gravel has also been investigated. However, after solidification the sulfur in these concretes undergoes allotropic transformation wherein the sulfur reverts to the more dense orthorhombic form which results in a product that is highly stressed and therefore vulnerable to failure by cracking.
Improvements in sulfur based cement formulations have been achieved by adding a modifier component to the cement formulations. Diehl (New Uses For Sulfur and Pyrites, Madrid Symposium of the Sulfur Institute, 1976) has shown improved sulfur concrete formulations by the addition of small quantities of dicyclopentadiene as a modifier to the sulfur. Such modified cement formulations exhibit improved compressive strength characteristics.
McBee et al in the Utilization of Secondary Sulfur In Construction Materials (Proceedings of the Fifth Mineral Waste Utilization Symposium, 1976) have shown a variety of sulfur cement formulations such as sulfur concretes, sand-sulfur-asphalt paving and the like wherein the sulfur binder component is modified by the presence of small quantities of dicyclopentadiene. Sullivan et al in the Development and Testing of Superior Sulfur Concretes, 1976 and in studies of Sand-Sulfur-Asphalt Paving Materials, 1975 (both Bureau of Mines Reports of Investigations) have also described various sulfur cement formulations in which the sulfur binder is modified with dicyclopentadiene. Sullivan et al in Sulfur In Coatings and Structural Materials, Advances In Chemistry No. 140 have also described sulfur cement formulations in which dicyclopentadiene, dipentene, methylcyclopentadiene, styrene and an olefinic liquid hydrocarbon were investigated as modifiers. While the modification of sulfur cement formulations with various unsaturated hydrocarbon materials results in cement formulations of improved characteristics, nevertheless a need has continued to exist for modified sulfur cement formulations of improved freeze-thaw stability and strength characteristics.